An offset printing method based on the inkjet scheme is described in PTL 1. The method described in PTL 1 includes a first step of printing a UV ink image on a flat original sheet by using inkjet printing with a UV ink, a second step of irradiating the UV ink image with UV or an electron beam to bring the UV ink image to a semi-dry state while the UV ink image is being printed or immediately after the UV ink image is printed, a third step of transferring the semi-dry UV ink image to an elastic blanket surface, a fourth step of offset printing the transferred UV ink image from the elastic blanket to a printing object, and a step of drying and fixing the UV ink image formed by the offset printing.